Customer is testing SIP using TCP as transport layer. However, he doesn't see the transport tag in the Contact Header. After examining the trace, it is found that the SUT is not attaching tcp as transport in the URI Request Line.
Abacus will check if there is any transport tag in the request line. If there is none, it will not add the tag in the contact header, even though the system has been configured to use TCP. There is a work around for this issue: user can create a filter to parse the Request Line and append the transport to the message. After that, Abacus will add the tcp transport tag in the Contact Header.